Possible Clues:

• Doctor wants side of blade to scoop out
• Is the doctor on the side of this to get to the bottom of it?
• Search the bottom
• Clean out the bed of a river or harbour
• Scoop up mud and silt from harbour bottom
• Change channels?
• Clean out river bed
• Get the doctor to the side up from the bottom
• Remove material from a channel or riverbed
• Will the doctor get over the side and get to the bottom of this?